When you hyperextended it, if it dislocated or stretched the nerves too far they can break which may lead to numbness. However, they SHOULD regrow given some time. One would hope.
Massage the area + obviously rehab to get blood flowing to the area to help speed up healing. Might want to do some myofascial in the area to see if it's just an impingement or something.
Also, I'd talk to your PT if you can... see if they know if anything could be up. This is my best non-medical, non-PT guess.